A hub-bearing assembly serves to rotatably mount a soil-working disc (D) on a supporting axle (A) of an agricultural machine. The assembly comprises a hub-bearing unit (10) and a sealing device (20). The a hub-bearing unit has a radially outer, rotatable outer race (11) from one side of which a flange (12) radially extends for mounting a disc (D). The sealing device (20) is mounted on a side of the hub-bearing unit opposite to the side of the flange (12). The radially outer surface of the assembly has a portion (38) intermediate the flange (12) and the side of the sealing device (20), which is radially recessed so as to serve as a preferential seat for winding wires picked up from the fields during use of the agricultural machine.
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13. An assembly comprising:
a soil-working disc for an agricultural machine, the disc being mounted to a radial flange extending from one side of a rotatable outer race of a hub-bearing unit, and
a sealing device mounted adjacent to and outside of the single radially outer, rotatable outer race and on a side of the hub-bearing unit opposite to the side of the flange,
wherein a single radially outer surface of the assembly has a portion located intermediate the flange and the side of the sealing device and radially recessed with respect to the radially outer surface so as to provide a seat for winding wires picked up from fields during use of the agricultural machine; and wherein
the rotatable outer race is provided with raceways for bearing balls; and wherein
the radially recessed portion in the seat is designed to funnel, reel and properly coil the wires to be picked up from the fields.
1. A hub-bearing assembly for rotatably mounting a soil-working disc on a supporting axle of an agricultural machine, the hub-bearing assembly comprising:
a hub-bearing unit with a single radially outer, rotatable outer race from one side of which a flange radially extends for mounting the disc, and
a sealing device mounted adjacent to and outside of the single radially outer, rotatable outer race and on a side of the hub-bearing unit opposite to the one side of the flange,
wherein a radially outer surface of the assembly has a portion located intermediate the flange and the side of the sealing device and radially recessed with respect to the radially outer surface so as to provide a seat for winding wires picked up from the fields during use of the agricultural machine; and wherein
the single radially outer, rotatable outer race is provided with raceways for bearing balls; and wherein
the radial recess in the seat is designed to funnel, reel and properly coil the wires to be picked up from the fields.
2. The assembly of
3. The assembly of
the rotatable part of the sealing device includes the shield having a substantially L-shaped axial cross section, with an outer cylindrical axial wall and a radial wall extending towards the axis of rotation of the assembly, the elastic gasket of the rotatable part forming a radial sealing lip and an elongate axial sealing lip the radial sealing lip and the elongate axial sealing lip being fixed to the radial wall;
the stationary part of the sealing device is fixable to the supporting axle and includes the shield having a substantially C-shaped axial cross section with an inner cylindrical wall and a radial wall, the radial sealing lip being engaged with the inner cylindrical wall and an end of the elongate axial sealing lip being slidable against the radial wall of the stationary part, and an outer cylindrical wall disposed coaxially about the inner cylindrical wall, an elastic gasket of the stationary part being fixed on the outer cylindrical wall and includes a set of parallel radial lips slidable against the outer cylindrical wall of the rotatable part.
4. The assembly of
5. The assembly of
7. The assembly of
9. The assembly of
10. The assembly of
11. The assembly of
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The present invention refers to a hub-bearing assembly fort a soil working disc, particularly a tilling disc.
These discs are usually arranged side to side on respective axles projecting from the frame of the plough or another similar agricultural machine. Each disc is rotatably mounted by means of a hub-bearing unit comprised of one or two stationary, radially inner races, fixed on a central axle projecting from an arm of the agricultural machine frame, a radially outer race which is integral with a radial outer flange for mounting the disc, and a dual set of balls interposed between the inner and outer races. The inner races, and therefore the whole bearing unit, are axially locked against a shoulder of the axle by tightening a ring nut screwed on the free outer end of the axle. See, for example, EP-B-1 326 489.
In order to prevent contaminants (water, mud, soil) from entering the bearing from the side opposite to that where the disc is mounted, i.e. on the side facing the arm of the frame, some bearing units have been equipped with sealing devices having sealing lips slidingly contacting interface shields. The sealing devices used heretofore have not proven to guarantee efficient sealing for long enough time, particularly if the locking nut is slightly unscrewed or loose.
Efficient sealing action is of primary importance for correct operation of the disc over an acceptable period of time. Since the contamination conditions are extreme, contaminants entering the inner parts of the bearing may rapidly lead to the locking of a disc, consequently reducing productivity. In some cases the entering of contaminants is due to the locking nut being partially unscrewed on the free end of the axle. Also, an efficient sealing action able to prevent leakage of lubricant out of the bearing is of primary importance for the protection of the environment, in order to prevent pollution of the soil by the lubricant.
The performance and life of sealing devices are also limited by metal wires that are used for tying up rolled bales and that are left on the field. These wires are inevitably picked up by the discs and tightly wound around the hubs, forming rather thick coils. The same wires, tangled around and beside the sealing device may destabilize it or move part of it so that the lips of the sealing device are no longer correctly positioned on the respective interface surfaces.
It is a general object of this invention to provide a highly reliable hub-bearing assembly allowing servicing to become less frequent, also under heavy duty conditions. A particular object of this invention is to guarantee sealing action with time against external contaminants. Another object of this invention is to provide an assembly having a reduced axial bulk, allowing to bring the discs nearer to one another and therefore increase, on a same agricultural machine, the number of discs, without adversely affecting the performance of the sealing devices.
These and other objects and advantages, which will be better understood in the following, are achieved according to the invention by a hub-bearing assembly having the features defined in claim 1. According to another aspect, the invention provides an assembly as defined in claim 14. Preferred embodiments of the invention are set forth in the dependent claims.
A few preferred, but not limiting embodiments of the invention will now be described, reference being made to the appended drawings, in which:
Referring initially to
The hub-bearing unit comprises a rotatable outer race 11 forming on one side a radial flange 12 for mounting the disc D by means of bolts B fitted in a number of axial bores 13. A dual set of bearing balls 14, 15 is interposed between the outer race 11 and a pair of inner races 16, 17 tightly mounted side to side on a central axle A projecting from an arm E of the frame of an agricultural machine. The inner races 16, 17 are axially clamped in position against a shoulder S of the axle by means of a ring nut G screwed on the free end of axle A. On the side facing the disc D, an O-ring gasket 18 is accommodated in a circular groove 19 and pressed between the outer race 11 and the disc D for ensuring sealing action against contaminants accessing the inner parts of the bearing. Furthermore, the sealing action is improved by a cap C which closes the outer race 11 on the side of disc D.
The cassette sealing device 20 is fitted on the side of the unit 10 opposite to that where the disc D is located. The sealing device 20 consists of a rotatable part and a stationary part. As shown more clearly in
It will be noted that, owing to the above arrangement, the lips of the two gaskets of the sealing device 20 are substantially co-planar, i.e. they are contained in a very narrow axial space, which gives the sealing device and overall compact size and, consequently, contributes to reduce the axial size of the assembly as a whole. By way of indication, a hub-bearing assembly according to the invention allows to reduce the bulk by about 10% with respect to conventional assemblies, and therefore, allows to increase the number of discs in an agricultural machine and improve its efficiency. Experimental tests carried out by the applicant have shown that the sealing device 20 performs an efficient action also in case the ring nut G is partly unscrewed, in a condition where the assembly has acquired an axial play of 1-2 mm with respect to the supporting axle A. The axially compact arrangement allows to add a side shield 39 in the form of an annular disc that is fixed to the axle A near the sealing device 20. The side shield 39 cooperates with the sealing device 20 performing an additional labyrinth sealing action and protecting the sealing device 20.
In the embodiments shown in
The embodiment shown in
In the embodiments of
An important feature of the present invention is that the radially outer surface of the hub-bearing assembly has a central zone 38, intermediate the side of the flange 12 and the opposite side where the sealing device 20 is mounted, which is radially recessed. The recessed zone 38 serves as a preferential seat where the wires picked up during use of the agricultural machine are conveyed and wound. These wires are so wound in a zone which is spaced from the side of the sealing device, and therefore do not adversely affect its correct operation. In other words, a channel open in a radially outer direction is formed around the hub, where the said metal wires are conveyed and wound.
It will be observed that in the embodiment of
The invention is not intended to be limited to the embodiments described and illustrated herein, which should be considered as examples of the assembly; rather, the invention may be modified with regard to the shape and arrangement of parts, and to constructional and functional details, as will be apparent to those skilled in the art.
Fadda, Gianmario, Urso, Stefano, Concu, Cristian, Sassi, Mauro, Andersson, Ove L., Dellamore, Lorenzo, Giovannelli, Maurizio, Husslein, Wolfgang
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